[en] Research of microstructure of the medium carbon chrome-silicon steel modified by Fe-Al₂O₃ ligature (×20000), shows that nano-particles are located on borders of grains. As a result metal is strengthened. Researches of wear resistance and mechanical properties of carbon-manganese austenitic (Hadfield) steel and medium carbon chrome-silicon steel is carrying out. The testing for wear revealed that in both cases, the nano-reagent (Fe-Al₂O₃) modified steels are characterized by high wear resistance. Numerically increment in wear resistance is 22 - 26 %. The mechanical properties of Hadfield steel are presented according to the results of industrial smelting. The tensile strength of steel modified by nano Fe-Al₂O₃ increased by 28 % (from 629 to 876 MPa), elongation - by 27 % (from 24 to 33 %). After the rolling, the tensile strength of medium carbon chromium-silicon steel modified by nano Fe-Al₂O₃ was 1208 MPa, which exceeds in 22 %, but of the same grade conventional steel - 943 MPa exceeds by 22 %. Prevention (full or partial) of the formation of nanoparticles' aggregates is revealed. It is possible using special nano-sized elements-dispersants, such as Ni, Mo, B and Co. Along with dispersants these elements can also be alloying. Technology of manufacturing Fe-Al₂O₃-Ni, Fe-Al₂O₃-Mo, Fe-Al₂O₃-B, and Fe-Al₂O₃-Co nanocomposites is developed. The resulting composite compounds are characterized by high dispersion. By extension X-ray diffraction peaks (Scherer method) the size of the nano-particles was estimated as 30 - 80 nm, which is also confirmed by electron microscopic examinations. (author)